1. Field of the Invention
This invention relates to a heat exchanger comprised of an inner tube fitted with a spiral member therein, and an outer tube, and in which heat exchange of fluid, above all, liquid, is carried out between the inner and outer tubes.
2. Related Art and Problem
It has been known with conventional heat exchangers to provide a large number of heat transfer fins and baffle plates to improve the heat transfer rate. However, with this type of heat exchangers, so-called channeling phenomenon in which the fluid flows as a laminar flow, is produced, thereby placing limitation in improving the heat exchange performance.
It has also been known to use a so-called static mixer in which baffle plates with a twist of 180.degree. are alternately connected to one another in an inverse direction each with a connection angle of 90.degree.. However, the structure tends to be complicated due to the increased number of interconnections, and a large number of process steps are required in production. This presents a grave problem if it is necessary to provide a large number of the inner tubes or to provide a large heat transfer area with the use of an elongated tube. Besides, the conventional static mixer undergoes considerable pressure loss and hence is not satisfactory from the viewpoint of energy saving.